One-dimensional Au/Si heterojunction-microstructure and phase evolution under electron beam irradiation

A special type of Au/Si nanowire heterojunctions, which are wrapped by SiO2 surface layer, is demonstrated in this work. Nanochannels exist in-between the Si-core/SiO2-sheath close to the junction, which provides a flowing path for the Au at elevated temperatures. The Au-Si interactions during the reversible flowing process lead to an interesting phase evolution of the junction system, which eventually result in self-formation of the secondary nanostructures at the original Si/SiO2 interface. The observed microstructure/phase evolution of the Au-Si nanowire junction under the focused electron beam irradiation suggests an approach to modify and pattern the Si nanowire surface, which may have potential applications in the nanoelectronic industry